[PATCH v4 10/16] fsnotify: Support passing argument to insert callback on add_event

[Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>]

FAN_FS_ERROR requires some initialization to happen from inside the
insert hook.  This allows a user of fanotify_add_event to pass an
argument to be sent to the insert callback.

Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx>
---
 fs/notify/fanotify/fanotify.c    | 5 +++--
 fs/notify/notification.c         | 6 ++++--
 include/linux/fsnotify_backend.h | 6 ++++--
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 93f96589ad1e..912d120b9e48 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -695,7 +695,8 @@ static __kernel_fsid_t fanotify_get_fsid(struct fsnotify_iter_info *iter_info)
  * Add an event to hash table for faster merge.
  */
 static void fanotify_insert_event(struct fsnotify_group *group,
-				  struct fsnotify_event *fsn_event)
+				  struct fsnotify_event *fsn_event,
+				  const void *data)
 {
 	struct fanotify_event *event = FANOTIFY_E(fsn_event);
 	unsigned int bucket = fanotify_event_hash_bucket(group, event);
@@ -779,7 +780,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
 
 	fsn_event = &event->fse;
 	ret = fsnotify_insert_event(group, fsn_event, fanotify_merge,
-				    fanotify_insert_event);
+				    fanotify_insert_event, NULL);
 	if (ret) {
 		/* Permission events shouldn't be merged */
 		BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 44bb10f50715..206a17346ca6 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -83,7 +83,9 @@ int fsnotify_insert_event(struct fsnotify_group *group,
 			  int (*merge)(struct fsnotify_group *,
 				       struct fsnotify_event *),
 			  void (*insert)(struct fsnotify_group *,
-					 struct fsnotify_event *))
+					 struct fsnotify_event *,
+					 const void *),
+			  const void *insert_data)
 {
 	int ret = 0;
 	struct list_head *list = &group->notification_list;
@@ -121,7 +123,7 @@ int fsnotify_insert_event(struct fsnotify_group *group,
 	group->q_len++;
 	list_add_tail(&event->list, list);
 	if (insert)
-		insert(group, event);
+		insert(group, event, insert_data);
 	spin_unlock(&group->notification_lock);
 
 	wake_up(&group->notification_waitq);
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 435982f88687..ff2cf04c7496 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -527,14 +527,16 @@ extern int fsnotify_insert_event(struct fsnotify_group *group,
 				 int (*merge)(struct fsnotify_group *,
 					      struct fsnotify_event *),
 				 void (*insert)(struct fsnotify_group *,
-						struct fsnotify_event *));
+						struct fsnotify_event *,
+						const void *),
+				 const void *insert_data);
 
 static inline int fsnotify_add_event(struct fsnotify_group *group,
 				     struct fsnotify_event *event,
 				     int (*merge)(struct fsnotify_group *,
 						  struct fsnotify_event *))
 {
-	return fsnotify_insert_event(group, event, merge, NULL);
+	return fsnotify_insert_event(group, event, merge, NULL, NULL);
 }
 
 /* Queue overflow event to a notification group */
-- 
2.32.0